If I'm going to a bike event where everyone else is wearing lycra - I'll just wear my lycra bike shorts.

If I'm biking with my brother or something like that, I've no desire to inflict my jiggly spandex clad butt upon him, and just stick on a pair of loose nylon shorts over my bike shorts. There are really some things you'd rather not see your family members wearing. I've got a couple of pearl izumi loose nylon short. I think they came with thin liner shorts, which I use when I'm on the trainer, and just replace with regular bike shorts.

I tend to get bike jerseys that are more casual looking. Loose longer ones that cover up a little are nice.